Morepath 0.4 has a breaking change to the way application reuse
works. Don't worry, you can fix your code by making a few minor
changes. In short, Morepath application objects are now classes, not
instances, and you can instantiate this class to get a WSGI
object. See the CHANGES for a lot of details on what happened and
what you need to do.

The big win is that application reuse in Morepath has become Python
subclassing, and that making a WSGI application (even a parameterized
one) is just instantiating the class.

The other win is that Morepath gained even more extensibility
features, namely the ability for Morepath extension to introduce new
Morepath directives (the decorators you see everywhere in Morepath
examples). But I can't talk too much about that until I document them
properly.

Along with the new Morepath, I've also made the initial release of
BowerStatic (announcement). BowerStatic is the WSGI framework that
lets you easily include bower-installed resources in your web page and
do the right thing with caching (forever, thank you, but on a separate
URL for each version).

How does that relate to Morepath, you may ask? Well, today I've also
released the Morepath integration for BowerStatic,
more.static. I've described in the Morepath documentation what to
do to get it working in your Morepath project. The reason Morepath
0.4 had the breaking change was in part to support more.static,
which needed the ability to introduce a new Morepath directive among
other things.